Ya'll talkin' about a turd hearse??
The problem with the hearse is threefold. Storage, capacity and weight. First, how and where are you gonna carry it to the campsight. Hopefully not like Jed Clampett over a ladder rung. Second, How large of a tank do you want? The larger ones will hold a bunch of waste but that brings you to the final dillemma. Weight. At approx 7lbs per gallon, you do the math. If your on uneven terrain or have to drag that thing uphill....good luck. For the cost and inconvenience I'd rather hire the Honey Wagon.